Enhancement of Hard Magnetic Properties in Fraktal-Like Nano and Mesoscopic Grains

The paper refers to Monte Carlo magnetic simulations for fractal-like nano and mesoscopic grains. The analyzed objects differed in the size, surface development, magnetic anisotropy and the spin values attributed to the system nodes inside the fractal. Such an approach allowed us to determine their magnetization processes as well as optimization characteristics in the direction to enhancement of hard magnetic properties. As it was shown, the size effects depend on the chosen value of magnetic anisotropy. In the case of fractals with ultra-high coercivity, the decreasing of their size leads to deterioration of coercivity, especially for the high surface to volume ratio. Opposite effects were observed for soft magnetic fractals when the nanostructure caused an appearance of the coercive field, and the maximum of energy product was predictably significantly higher than for conventional rare earths' free permanent magnets.

Automated summary

The paper discusses Monte Carlo magnetic simulations for fractal-like nano and mesoscopic grains, showing that the size effects depend on the chosen value of magnetic anisotropy. For fractals with ultra-high coercivity, decreasing their size leads to deterioration of coercivity, especially for high surface to volume ratio, while soft magnetic fractals exhibit the opposite effect with the appearance of coercive field and significantly higher energy product than conventional rare earths' free permanent magnets.